Angiogenesis is a term used to describe the growth of new blood vessels. The growth and proliferation of blood vessels plays an important role in many biological processes. One example is tumor development, where the development of blood vessels within the tumor allows the tumor to grow through increased access to oxygen and nutrients, increases tumor survival, and facilitates tumor metastasis. Targeting angiogenesis is a promising route to treat cancer.
Angiogenesis in the eyes usually plays an important role in supply of sufficient oxygen and other necessary nutrients to the eyes and the development of normal tissues. However, when excessive and abnormal blood vessel development is occurred, ocular diseases, such as wet age-related macular degeneration (wet AMD) and diabetic macular edema (DME), can be induced, and in some cases, even blindness may result.
Age-related macular degeneration (AMD) is a disease that results from the degeneration of the retinal pigmented epithelium lining in the eye's macula, which leads to vision loss. The macula is a small area in the retina made up of the light-sensitive tissues lining the back of the eye and plays a critical role in central vision. AMD is one of the leading causes of blindness worldwide. AMD occurs in “wet” and “dry” forms. Wet AMD is the result of abnormal blood vessel growth in the retina. In wet AMD, increased amount of vascular endothelial growth factor (VEGF) contributes to this neovascularization, so therapeutic options include the use of VEGF inhibitors. However, many patients treated with VEGF inhibitors develop geographic atrophy (GA), which is a primary symptom of late dry macular degeneration, within a few years of treatment. Diabetic macular edema (DME) is a disease that resulted from swelling of the retina in diabetes mellitus due to leaking of fluid from blood vessels within the macula. The poor blood circulation in diabetic patients can accelerate the new blood vessel development in the macula, and retinal edema can result from the leakage of blood vessels with think or weak walls. DME is the leading cause of blindness in patients with diabetes, and 10% of the diabetics suffer from macular edema.